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A study on the prevalence of antibodies to Toxoplasma gondii in Singapore

Lim KC, Pillai R, Singh M

Southeast Asian J. Trop. Med. Public Health, 1982 Dec;13(4):547-50.
PMID: 6763354

The indirect fluorescence antibody technique has been employed to study the prevalence of toxoplasma antibodies in Singapore. 42.5% of clinically suspected cases of toxoplasmosis showed antibody titres. Of these, 17.5% had titres greater than or equal to 1.64. Malays and Indians have higher positive rates compared to the main ethnic group, the Chinese. Antibody titres are found in both males and females and span through the various age groups. The possible mode of transmission is discussed and the importance of congenital toxoplasmosis is indicated.
Definite stent thrombosis among Malaysian population: predictors and insights of mechanisms from intracoronary imaging

Lim KC, Yap LB, Amin AN

Med J Malaysia, 2020 09;75(5):472-478.
PMID: 32918412

INTRODUCTION: Stent thrombosis (ST) is an uncommon, but significant complication following angioplasty. We aimed to examine the predictors, clinical outcomes and mechanism of definite ST cases among patients who underwent percutaneous coronary intervention (PCI).
METHODS: This was a retrospective observational registry of 14,935 patients from the year 2011 till 2015. Clinical characteristics, clinical outcome and intracoronary imaging data were recorded in all the patients. The SPSS Statistic version 24 was used for statistical analysis. The Cox regression hazard model was used to report calculate the hazard ratio (HR) with a 95% confidence interval (95%CI). Independent predictors of ST were identified by univariate logistic regression analysis. Variables that showed a statistically significant effect in univariate analyses were entered in a multivariate Cox proportional hazards model. A p-value<0.05 was regarded as significant.
RESULTS: The incidence of definite ST was 0.25% (37 out of 14935 patients). 75% of ST group patients presented with ST elevation myocardial infarction (75% vs. 19.8%, p<0.01). There was higher mortality among patients with ST when compared to the group without ST (Hazard Ratio, HR=10.69, 95%CI: 1.13, 100). Two independent predictors of ST were 1) previous history of acute myocardial infarction (HR=2.36, 95%CI: 1.19, 4.70) and 2) PCI in the context of acute coronary syndrome when compared to elective PCI (HR=37, 95%CI: 15.7, 91.5). Examination of 19 ST cases with intracoronary imaging identified nine cases (47%) of underexpanded stents and five cases (26%) of malopposition of stents.
CONCLUSIONS: ST is associated with high mortality. PCI in acute coronary syndrome setting and a previous history of acute myocardial infarction were significant predictors for ST. Intracoronary imaging identified stent underexpansion and malopposition as common reasons for ST. In cases where the risk of ST is high, the use of intracoronary imaging guided PCI is recommended.
Fulltext Molecular and morphological analyses reveal phylogenetic relationships of stingrays focusing on the family Dasyatidae (Myliobatiformes)

Lim KC, Lim PE, Chong VC, Loh KH

PLoS One, 2015;10(4):e0120518.
PMID: 25867639 DOI: 10.1371/journal.pone.0120518

Elucidating the phylogenetic relationships of the current but problematic Dasyatidae (Order Myliobatiformes) was the first priority of the current study. Here, we studied three molecular gene markers of 43 species (COI gene), 33 species (ND2 gene) and 34 species (RAG1 gene) of stingrays to draft out the phylogenetic tree of the order. Nine character states were identified and used to confirm the molecularly constructed phylogenetic trees. Eight or more clades (at different hierarchical level) were identified for COI, ND2 and RAG1 genes in the Myliobatiformes including four clades containing members of the present Dasyatidae, thus rendering the latter non-monophyletic. The uncorrected p-distance between these four 'Dasytidae' clades when compared to the distance between formally known families confirmed that these four clades should be elevated to four separate families. We suggest a revision of the present classification, retaining the Dasyatidae (Dasyatis and Taeniurops species) but adding three new families namely, Neotrygonidae (Neotrygon and Taeniura species), Himanturidae (Himantura species) and Pastinachidae (Pastinachus species). Our result indicated the need to further review the classification of Dasyatis microps. By resolving the non-monophyletic problem, the suite of nine character states enables the natural classification of the Myliobatiformes into at least thirteen families based on morphology.
Infrequent occurrence of vancomycin-resistant enterococci in poultry from Malaysian wet markets

Ong CH, Asaad M, Lim KC, Ngeow YF

Malays J Pathol, 2002 Dec;24(2):91-4.
PMID: 12887166

Fifty samples of chicken, duck and geese faeces were obtained from 13 wet markets in Kuala Lumpur to study the prevalence of vancomycin-resistant enterococci (VRE) among local market poultry. Biotyping of colonies grown on azide agar incubated at 45 degrees C yielded E. pseudoavium, E. faecalis, E. faecium and E. gallinarum from chicken faeces and E. malodoratus, E. faecalis, E. faecium, E. gallinarum, E. hirae/dispar, and E. durans from goose and duck faeces. On agar containing 6 mg/ l of vancomycin, one strain of E. flavescens was identified, giving a VRE detection rate of 2.0%. This isolate had a vancomycin M.I.C. of 8 mg/l as determined by the Etest, and the van C-3 gene that was identified by PCR followed by sequence analysis. The prevalence of VRE among poultry sold in local markets appears to be low, and may reflect the infrequent use of antimicrobials in our poultry farms. Nevertheless, the possibility of human acquisition of microbes via the food chain cautions against the use of antimicrobials in animal husbandry that may encourage the emergence and spread of multi-drug resistant organisms like the VRE among animal microbial flora.
Zoonotic implications of cats and dogs in filarial transmission in Peninsular Malaysia

Mak JW, Yen PK, Lim KC, Ramiah N

Trop Geogr Med, 1980 Sep;32(3):259-64.
PMID: 7210162

Filarial infections in 447 cats and 68 dogs from six endemic areas of human filariasis in Peninsular Malaysia were studied as part of the study on the zoonotic transmission of subperiodic Brugia malayi infection. 20.6% of cats and 57.4% of dogs had filarial infections. Cats were infected with subperiodic B. malayi, B. pahangi, Dirofilaria repens and D. immitis. Dogs were infected with B. pahangi and D. immitis. 6.9% of the cats had subperiodic B. malayi infection. The zoonotic implications of these infections and their impact on the filariasis control programme in Peninsular Malaysia were discussed.
Dietary astaxanthin augments disease resistance of Asian seabass, Lates calcarifer (Bloch, 1790), against Vibrio alginolyticus infection

Lim KC, Yusoff FM, Shariff M, Kamarudin MS

Fish Shellfish Immunol, 2021 Jul;114:90-101.
PMID: 33838221 DOI: 10.1016/j.fsi.2021.03.025

This investigation describes the impacts of dietary provisioning with astaxanthin on hemato-biochemistry, non-specific immunity, and disease resistance of the Asian seabass, Lates calcarifer, against the virulent Vibrio alginolyticus; with specific reference to dose-response associations and variations over different post-infection periods (0-, 7-, and 14-day). Triplicate groups of fish weighing 28 g, on average, were fed various diets (C, the control or astaxanthin-free; AXT50, 50 mg astaxanthin kg-1 diet; AXT100, 100 mg astaxanthin kg-1 diet; and AXT150, 150 mg astaxanthin kg-1 diet) for 90 days and subsequently challenged with V. alginolyticus at the end of the feeding period. Experimental infection unveiled that supplemented fish demonstrated significant improvements (P
Fulltext Feeding ecology and reproductive biology of small coastal sharks in Malaysian waters

Lim KC, Then AY, Loh KH

PeerJ, 2023;11:e15849.
PMID: 37637173 DOI: 10.7717/peerj.15849

Small coastal demersal sharks form a major proportion of the sharks landed in Malaysia. However, little is known about their feeding ecology and reproduction. This study sought to elucidate the dietary patterns, role of ontogeny in prey consumption, and reproductive biology of four dominant small demersal shark species in Malaysian waters: the Hasselt's bamboo shark, Chiloscyllium hasseltii; brownbanded bamboo shark, C. punctatum; spadenose shark, Scoliodon laticaudus; and Pacific spadenose shark, S. macrorhynchos. Dietary analyses revealed a high overlap in prey taxa consumed; clear resource partitioning among co-occurring species based on the percentage Prey-specific Index of Relative Importance (%PSIRI), with higher fish %PSIRI for Chiloscyllium hasseltii, higher cephalopod %PSIRI for C. punctatum, and higher crustacean %PSIRI for both Scoliodon species; and an ontogenetic diet shift, seen through changes in prey size. Based on the examination of reproductive organs, the results showed larger sizes at maturity for males compared to females for all four species; no obvious reproductive cycles, based on hepatosomatic and gonadosomatic indices for all species; female bias in the sex ratio of the embryos of Scoliodon species; and increased reproductive output (number of eggs or embryos and size of eggs) with larger female size for C. hasseltii and Scoliodon species. The partitioning of food resources minimizes direct competition for food and supports coexistence within shared coastal habitats. The reproductive strategies of these small coastal sharks appear to be favorable for supporting short-term population productivity; although a reduction in fishing pressure, especially from bottom trawlers, is essential for the long-term sustainable use of these sharks.
Fulltext Brown banded bamboo shark (Chiloscyllium punctatum) shows high genetic diversity and differentiation in Malaysian waters

Lim KC, Then AY, Wee AKS, Sade A, Rumpet R, Loh KH

Sci Rep, 2021 Jul 21;11(1):14874.
PMID: 34290296 DOI: 10.1038/s41598-021-94257-7

The demersal brown banded bamboo shark Chiloscyllium punctatum is a major component of sharks landed in Malaysia. However, little is known about their population structure and the effect of high fishing pressure on these weak swimming sharks. Both mitochondrial DNA control region (1072 bp) and NADH dehydrogenase subunit 2 (1044 bp) were used to elucidate the genetic structure and connectivity of C. punctatum among five major areas within the Sundaland region. Our findings revealed (i) strong genetic structure with little present day mixing between the major areas, (ii) high intra-population genetic diversity with unique haplotypes, (iii) significant correlation between genetic differentiation and geographical distance coupled with detectable presence of fine scale geographical barriers (i.e. the South China Sea), (iv) historical directional gene flow from the east coast of Peninsular Malaysia towards the west coast and Borneo, and (v) no detectable genetic differentiation along the coastline of east Peninsular Malaysia. Genetic patterns inferred from the mitochondrial DNA loci were consistent with the strong coastal shelf association in this species, the presence of contemporary barriers shaped by benthic features, and limited current-driven egg dispersal. Fine scale population structure of C. punctatum highlights the need to improve genetic understanding for fishery management and conservation of other small-sized sharks.
Fulltext Efficacy of Single and Multi-Strain Probiotics on In Vitro Strain Compatibility, Pathogen Inhibition, Biofilm Formation Capability, and Stress Tolerance

Puvanasundram P, Chong CM, Sabri S, Yusoff MSM, Lim KC, Karim M

Biology (Basel), 2022 Nov 10;11(11).
PMID: 36358345 DOI: 10.3390/biology11111644

Compatibility of each strain in a multi-strain probiotic (MSP), along with its properties, becomes a strong base for its formulation. In this study, single-strain probiotics (SSPs) and multi-strain probiotics (MSPs) were evaluated in vitro for strain compatibility, microbial antagonism, biofilm formation capacity, and stress tolerance. Bacillus amyloliquefaciens L11, Enterococcus hirae LAB3, and Lysinibacillus fusiformis SPS11 were chosen as MSP1 candidates because they showed much stronger antagonism to Aeromonas hydrophila and Streptococcus agalactiae than a single probiotic. MSP 2 candidates were Lysinibacillus fusiformis strains SPS11, A1, and Lysinibacillus sphaericus strain NAS32 because the inhibition zone produced by MSP 2 against Vibrio harveyi and Vibrio parahaemolyticus was much higher than that produced by its constituent SSPs. MSP1 in the co-culture assay reduced (p < 0.05) A. hydrophila count from 9.89 ± 0.1 CFU mL−1 to 2.14 ± 0.2 CFU mL−1. The biofilm formation of both MSPs were significantly higher (p < 0.05) than its constituent SSPs and the pathogens. The SSPs in both MSPs generally showed resistance to high temperatures (80, 90, and 100 °C) and a wide range of pH (2 to 9). This in vitro assessment study demonstrates that MSP1 and 2 have the potential to be further explored as multi-strain probiotics on selected aquatic species.
Clinical and radiological outcomes of SARS-CoV-2 related organising pneumonia in COVID-19 survivors

Kho SS, Lim KC, Muhammad NA, Nasaruddin MZ, Ismail I, Daut UM, et al.

Med J Malaysia, 2023 Mar;78(2):131-138.
PMID: 36988520

INTRODUCTION: COVID-19 patients frequently demonstrate radiological organising pneumonia (OP) pattern. The longterm outcome and treatment options for this group of patients remain uncertain. We aim to describe the clinical and radiological outcomes of patients with COVID-19-related OP and identify possible clinical factors associated with inferior radiological outcome.
MATERIALS AND METHODS: Post-COVID-19 clinic attendees, consisting of post-COVID-19 patients discharged from major hospitals in the state of Selangor during the third pandemic wave of COVID-19 in Malaysia, were enrolled in this retrospective study for 6 months. Physician-scored Modified Medical Research Council (mMRC), patient self-reported quality of life (EQ-VAS) score and follow-up CT scan were evaluated.
RESULTS: Our cohort comprised 131 patients, with a median age of 52 (IQR 39-60) years and median BMI of 29.40 (IQR 25.59-34.72). Majority (72.5%) had co-morbidities, and 97.7% had severe disease requiring supplementary oxygen support during the acute COVID-19 episode. 56.5% required intensive care; among which one-third were invasively ventilated. Median equivalent dose of methylprednisolone prescribed was 2.60 (IQR 1.29-5.18) mg/kg during admission, while the median prednisolone dose upon discharge was 0.64 (IQR 0.51-0.78) mg/kg. It was tapered over a median of 8.0 (IQR 5.8-9.0) weeks. Upon follow-up at 11 (IQR 8-15) weeks, one-third of patients remained symptomatic, with cough, fatigue and dyspnoea being the most reported symptoms. mMRC and EQ-VAS scores improved significantly (p<0.001) during follow-up. Repeat CT scans were done in 59.5% of patients, with 94.8% of them demonstrating improvement. In fact, 51.7% had complete radiological resolution. Intensive care admission and mechanical ventilation are among the factors which were associated with poorer radiological outcomes, p<0.05.
CONCLUSION: Approximately one-third of patients with SARSCoV- 2-related OP remained symptomatic at 3 months of follow-up. Majority demonstrated favourable radiological outcomes at 5-month reassessment, except those who required intensive care unit admission and mechanical ventilation.
Evaluating Bacillus flexus as bioremediators for ammonia removal in shrimp culture water and wastewater and characterizing microbial communities in shrimp pond sludge

Jasmin MY, Isa NM, Kamarudin MS, Lim KC, Karim M

Braz J Microbiol, 2024 Mar;55(1):529-536.
PMID: 38280093 DOI: 10.1007/s42770-024-01246-9

The accumulation of nitrogen compounds in shrimp farming water and effluent presents a major challenge. Ammonia is a form of nitrogen that limits shrimp growth due to its potential toxicity and effects on shrimp health and water quality. This study is aimed at identifying promising bioremediators from shrimp pond sludge to mitigate ammonia levels in both culture water and wastewater and at determining major bacterial communities in sludge using metagenomic analysis. A sludge sample was collected from a shrimp pond in Selangor, Malaysia, to isolate potential ammonia-removing bacteria. Out of 64 isolated strains, Bacillus flexus SS2 showed the highest growth in synthetic basal media (SBM) containing ammonium sulfate at a concentration of 70 mg/L as the sole nitrogen source. The strain was then incubated in SBM with varying pH levels and showed optimal growth at pH 6.5-7. After 24 h of incubation, B. flexus SS2 reduced the ammonia concentration from an initial concentration of 5 to 0.01 mg/L, indicating a 99.61% reduction rate, which was highest in SBM at pH 7. Moreover, the strain showed ammonia removal ability at concentrations ranging from 5 to 70 mg/L. Metagenomic analysis revealed that Proteobacteria was the most abundant phylum in the sludge, followed by Cyanobacteria, Actinobacteria, Chloraflexi, Firmicutes, and Campilobacterota. Bacillus flexus SS2 belongs to the Bacillota phylum and has the potential to serve as a bioremediator for removing ammonia from shrimp culture water and wastewater.
Fulltext Advancing DNA Barcoding to Elucidate Elasmobranch Biodiversity in Malaysian Waters

Loh KH, Lim KC, Then AY, Adam S, Leung AJ, Hu W, et al.

Animals (Basel), 2023 Mar 09;13(6).
PMID: 36978544 DOI: 10.3390/ani13061002

The data provided in this article are partial fragments of the Cytochrome c oxidase subunit 1 mitochondrial gene (CO1) sequences of 175 tissues sampled from sharks and batoids collected from Malaysian waters, from June 2015 to June 2022. The barcoding was done randomly for six specimens from each species, so as to authenticate the code. We generated barcodes for 67 different species in 20 families and 11 orders. DNA was extracted from the tissue samples following the Chelex protocols and amplified by polymerase chain reaction (PCR) using the barcoding universal primers FishF2 and FishR2. A total of 654 base pairs (bp) of barcode CO1 gene from 175 samples were sequenced and analysed. The genetic sequences were blasted into the NCBI GenBank and Barcode of Life Data System (BOLD). A review of the blast search confirmed that there were 68 valid species of sharks and batoids that occurred in Malaysian waters. We provided the data of the COI gene mid-point rooting phylogenetic relation trees and analysed the genetic distances among infra-class and order, intra-species, inter-specific, inter-genus, inter-familiar, and inter-order. We confirmed the addition of Squalus edmundsi, Carcharhinus amboinensis, Alopias superciliosus, and Myliobatis hamlyni as new records for Malaysia. The establishment of a comprehensive CO1 database for sharks and batoids will help facilitate the rapid monitoring and assessment of elasmobranch fisheries using environmental DNA methods.

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